Naphthalimide-based luminogens with bright aggregative-state emission: High-contrast blue-shift mechanofluorochromism and application in ink-free secure information storage.

In recent decades, with the advancement of the field of organic luminescent materials, mechanofluorochromic materials with aggregation-induced emission (AIE) properties have become a pioneering research hotspot due to their excellent photophysical properties and wide range of applications. Herein, a series of carbazole-naphthalamide (CN-R) type derivatives containing different benzene ring substituents and their isomers were designed and synthesized. The fluorescence of the donor-acceptor type derivatives could be modulated through the introduction of diverse benzene ring substituents. CNme-OCH3 demonstrated excellent AIE activity and a remarkable 74 nm force-induced fluorescence blue shift. Other compounds exhibited AIE or aggregation-induced emission enhancement (AIEE) properties. This innovative structural regulation strategy enables the design of organic materials with multiple photophysical properties. Moreover, the application of CNme-OCH3 in ink-free security information storage provides a new way to curb the increasingly serious counterfeiting phenomenon.